Phosphoric acid is a weak acid with the molecular formula H₃PO₄, appearing as a colorless, odorless liquid. This compound is non-flammable, has high volatility, and is relatively non-corrosive. The purity of this compound typically ranges from 54% to 85%, and it comes in both industrial and food-grade varieties.

One of the primary applications of phosphoric acid is in the food industry; it is used in the production of acidic foods and carbonated beverages, such as various types of cola, providing a tangy flavor to food. This compound also finds use in agriculture, as phosphorus is an essential element for plant growth. Organic phosphates are compounds that provide the energy necessary for most reactions occurring in living cells.

Phosphoric acid can be used directly to remove rust (iron(III) oxide) from iron or steel tools and convert iron into water-soluble phosphates. After rust removal, the iron phosphate produced transforms into black iron phosphate, which can serve as a corrosion inhibitor. Additionally, phosphoric acid is used as a catalyst in petrochemical industries. It is corrosive and can cause burns, pain, and redness in the eyes. Phosphoric acid should be stored in specially designed multi-layer plastic containers or stainless steel containers.